In the case of the Marine sniper/killer who wasn’t, Philadelphia Magazine did the right thing, after the fact, meaning after its April issue hit the stands.

When confronted with a crisis, you should follow the 3F rule – tell your story First, Fast and Fully.

Editor Tom McGrath went online, retracted and apologized for the story, which was based entirely on what subject John Boudreau told sports radio host Anthony Gargano, who has apologized for recklessly blowing by “red lights” and speeding “past all of the basic reporting.”to

This was an entirely different matter than the previous month’s “Being White in Philly” flap, which led to an apology tour to which most of the offended people weren’t even listening. But let’s not rehash that again. This month’s screw-up is much more damaging to the magazine’s journalistic credibility.

Boudreau, who had been an occasionally caller to Gargano’s show, claimed to be haunted by his past as a remorseless Marine killer.

Gargano was sympathetic to the (alleged) veteran -- it’s not clear at the moment that he actually served. Any of us might be sympathetic.

This is a classic illustration of the bromide, “If it seems too good to be true, it probably is.”

Gargano says he was “seduced” by Boudreau’s story, which is understandable, but then admits, “I didn’t verify his stories.” That is amazing and frightening.

Here’s where print journalism differs from talk radio, Facebook, Twitter and blogging. For print, you must verify the story. You simply must.

Many magazines have paid fact-checkers. Most newspapers don’t – the reporter is the fact-checker and the reporter can be quizzed by an editor, who might demand to see verifying documents, although the quiz might sometimes just be a question to the reporter: “Are you sure?”

McGrath apparently didn’t ask that question because Gargano could not have answered “yes.”

That might have even provided a “smell-the-coffee” moment to Gargano, who was so mesmerized by the story, and the sale of the story, he lost his bearings.

Philly magazine fact-checkers (I have dealt with them from time to time) apparently took a good look at individual pine and spruce trees but missed the forest. How could they have not verified Boudreau was actually a veteran?

I promised the veteran in question, who didn’t come to me voluntarily, anonymity and my word that I would shield him. I told him his story would give civilians an understanding of what the 1 percent who serve in the military go through. He reluctantly agreed, for that reason, to open people’s minds.

But before I wrote one word, I asked him to show me his army records, which he did, and photos of himself in Kuwait and Iraq. I then called the Pentagon to verify that someone by his name was actually where he claimed to be and when he claimed to be there.

The whole process took a number of days and then I interviewed (the name I gave him was John Milton) in his home and took pictures of him that did not show his face.

The reason I did all that was two-fold. First, as Gargano acknowledges, it’s basic reporting. Second, I live in fear that being lazy or careless or unprofessional could lead to a mistake that might wreck my professional reputation (such as it is, I say with a smile).

It’s my personal version of Fear Factor, but it’s got a great record of keeping my career from harm.

As for McGrath and Gargano, there was no intent to deceive and public humiliation is all the punishment that’s required.